In situ precipitation of amorphous and crystalline calcium sulphates in cellulose thin films

Abstract

A novel method for the in situ precipitation of calcium sulphates within spin coated cellulose thin films is described. A key feature of the approach is the use of N-methylmorpholine N-oxide (NMMO) not only to dissolve fibrous cellulose but also to stabilize nanoparticles of amorphous calcium sulphate prior to regeneration of the polysaccharide matrix and formation of a thin composite film. Integration of the biopolymer film with amorphous or crystalline (bassanite, gypsum) calcium sulphate phases is influenced by the rate of NMMO hydration, providing a route to composite materials with stable or reactive inorganic materials that might find uses in diverse applications.